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DON LEMON, CNN ANCHOR: And also late last night, we also learned that the President is getting briefed on new details of the investigation into the Boston Marathon terror attack. The President has more meetings scheduled today with other senior officials as well.

For more information on that we want to go to CNN's Brianna Keilar she is live at the White House, Brianna all of the security is going to be compounded tomorrow with the Secret Service and the President's motorcade as he enters and exists town.

BRIANNA KEILAR, CNN WHITE HOUSE CORRESPONDENT: That's right, Don. And he's been keeping an eye on the investigation led by the FBI. He is being briefed today by his homeland security advisor Lisa Monaco as well as FBI Director Robert Mueller and his Attorney General Eric Holder. He was also briefed overnight by Monaco.

Now tomorrow he does head to Boston. He'll be delivering remarks at that interfaith memorial services at the Cathedral of the Holy Cross and of course we're expecting this to be a very emotional event. Expect that President Obama will be very much serving in a role as Consoler-in-Chief as we've seen him unfortunately do on a number of occasions where we've seen tragedies like this.

He's reflected here in recent days. Yesterday he talked about those who had ran in this marathon, people who had gone through this grueling race and even after that went to the hospital to give blood for those who had been injured.

So I think we'll be hearing some of these anecdotes and moment of him of like kind of touching on sort of the tone and some of the inspirational stories that have come out to these terrible bombings -- Don.

LEMON: All right, Brianna Keilar at the White House. Brianna thank you very much.

When we come back, I want to tell you about new exclusive pictures of the bomb and the investigation and I will be talking live with one of the first people on the scene after that horrible blast. He's standing right here next to me.

We'll have more right after this break.

(COMMERCIAL BREAK) LEMON: Well this morning, a CNN exclusive in the terror attack in Boston. New information to tell you about just a couple of hours ago, Fran Townsend was the first to report that investigators found a lid to a pressure cooker believed to be used in the bombing. Now it was found in the rooftop and may help complete these images that surfaced overnight.

They show the remains of a pressure cooker, a shredded black backpack and what appeared to be metal pellets. A partial circuit board was also found suggesting that the bomb were possibly detonated by timers. The Boston law enforcement source says that the devices could pack about a gallon and a half of killing power.

Now according to CNN affiliate WHDH here in Boston, one of the bombs may be hidden inside this light colored bag on the sidewalk. And minutes later there was an explosion roughly where the bag sat.

Let's talk about the people who responded, who rushed in to danger. President Barack Obama praised the work of first responders who rushed into the chaos at the Boston Marathon but their heroism didn't end on Monday. Police and fire fighters in Boston are teaming up to offer a $50,000 reward for information on those bombers.

So joining me now is Rich Paris, he's the president of Boston Fire Local 718. First of all, thank you very much for what you do.

LEMON: You weren't one of the first on the scene, but your responders were the first to arrive, rushing into danger. And -- and they have experience. They know what to do when bombs go off.

PARIS: Yes, we had members work in the route that day along with Boston Police and Boston EMS. We train together. We are all -- on incidents like this -- marathons or any special events parades. We have teams out in the field and thank God they were there. They save lives and they all worked great together -- the police, the fire and EMS.

LEMON: Yes and so you have put together funds, you want to raise money, tell me about that.

PARIS: We are -- a victim's fund. It's the first responders' victim's fund. It's a at the Boston Firefighter's Credit Union that is at 60 Howard Street at Dorchester, Mass. 02124 and it's brought up through the Boston Police Unions, the EMS Union and the Boston Firefighters Union.

LEMON: What do you hope to accomplish with the money here in the fund?

PARIS: Well we're going to give -- 100 percent of that funds will go to the victims and whatever the victims need or we can just help their families out.

LEMON: Yes and again how can viewers help contribute you -- give us the address again.

LEMON: Ok we'll try to get that information up. We'll promise to get that information up. If you guys back there can hear on our "Impact your World", CNN.com/impact get it up how you can help the victims here.

Thank you very much, Boston Firefighter Rich Paris.

PARIS: Thank you very much.

LEMON: You're doing a great and please tell your guys and ladies that they're doing a wonderful job. Thank you so much. We appreciate you coming on CNN.

PARIS: Thanks for your support. Thank you.

LEMON: All right.

We'll be right back.

(COMMERCIAL BREAK)

CAROL COSTELLO, CNN ANCHOR: And we have been following this bit of breaking news all morning long.

The "Dallas Morning News" now reporting surprising new developments in the killings of a Kaufman County District Attorney and his wife and another prosecutor. Martin Savidge is on the phone. Have you managed to find out anything else about this -- this strange twist in this case?

MARTIN SAVIDGE, CNN CORRESPONDENT (via telephone): Authorities are still extremely tight lipped here. And we have reached out to many Carol. What's being reported is that Kim Williams, 46 years of age, was booked into the Kaufman County jail at 3:00 this morning and she has been charged with capital murder in connection with the murders of the district attorney, his wife and an assistant district attorney.

This is the first arrest that has been which has been directly tied to the murders of those three people that have shocked this rural county here in Texas. Now the connection Kim Williams, according to the "Dallas Morning News" who is said to be the wife of a former Justice of the Peace, that's Eric Williams.

And here is how this all fits into the scenario that authorities have talked about. Eric Williams last year was convicted of stealing county property. The man who directed his prosecution was the district attorney Mike McClelland and also the man who directly interviewed him and cross-examined him in the courtroom, that was Mark Hasse the two men that eventually end up dead. Is that any motivation for murder? That's what authorities have been looking into.

But I stress Carol even as recent as yesterday when I directly put that question to authorities, are you looking at Eric Williams. And they said right now he is not considered to be a suspect. Btu his wife definitely is at least according to the "Dallas Morning News" because she is behind bars and charged with capital murder -- Carol.

COSTELLO: So many questions left unanswered in this latest twist. Martin Savage, thank you so much. For more on this story, let's talk to FBI -- a former FBI assistant director and CNN analyst Tom Fuentes. He's in Washington.

So is it possible the wife might have had something to do with this -- with these murders and not the husband?

TOM FUENTES, FORMER ASSISTANT FBI DIRECTOR: Well I would say the fact that she's been charged with capital murder, it's a pretty clue that -- that it is very possible and probable that -- that she may have been involved at least according to what the police think.

I would like to add Carol that on April 2nd I did an Skype interview with Ed Lavendera because Ed had just been informed by Eric Williams' attorney that about four hours after the murder of the McClellands on the night of April, I mean March 31st when they were killed about four hours after work Williams met with the police at a restaurant in Kaufman and the police took swabs of his hands for gun powder residue.

So that would indicate that within hours of the -- of their murders, within hours of that that the police were already at least suspicious of the Williams. And the question of course --

(CROSSTALK)

COSTELLO: Hey Tom -- Tom can I -- can I have you pause a minute. I think your microphone fell off of your jacket can you check for us. Because we're having trouble hearing you.

Yes again a strange twist in this Kaufman Country Texas murder case, the wife of Eric Williams, who was at the very least a person of interest in this investigation. The wife of Eric Williams in now been placed under arrest and she is in jail being held on $10 million bond that's according to the "Dallas Morning Star". Ok, Tom, continue with what you were saying.

FUENTES: Ok I was saying that about four hours after the murders or after the police were discovering the murders, Williams' attorney reported to Ed Lavandera that his client, Eric Williams or may have been the wife now but they met with the police at a restaurant in Kaufman and again the same day as the killings March 31st and the police took swabs of the hands for gunpowder residue which is common in the case where you suspect someone of having shot somebody.

Now Ed was asking me at the time whether that would qualify them, or at least -- that Eric, if he was the person swabbed as a person of interest. And I said of course they wouldn't just go swabbing people at random. And the second thing about that is as you recall, when the murder was reported and it became public everybody was concerned that maybe this was part of an Aryan Brotherhood plot. Because maybe they had assisted in the massive arrest of 34 Aryan Brotherhood members back last November and that there was some kind of vendetta which there are no other information has come up.

So it showed that from the very beginning of the McClelland murders, the police were not focused on Aryan Brotherhood that they -- they were open-minded to the extent at least that they had strong suspicion to be looking at the Williams from the very first day.

COSTELLO: But why just charge the wife and not the husband?

FUENTES: Well, I think in this case, you know, They could still end up charging the husband. They're still examining evidence, and you also have the possibility that it could have been a murder for hire, you know. We may not have a situation where either the wife or the husband showed up at the McLelland residence and opened fire with a 223 assault weapon, you know, as happened.

So this could be that they hired someone else to do it, and there could be more that comes out about this case in the hours or next few days.

COSTELLO: Well, Martin Savidge is on it. Tom Fuentes, I know you are too. Thanks so much.

FUENTES: Ok Carol.

COSTELLO: Needless to say, it's a difficult time for many families in Boston right now. They're trying to understand why their loved ones were victims in this bombing at the Boston Marathon.

We're now learning more about the three people who were killed in those bombings. We'll tell you next.

(COMMERCIAL BREAK)

LEMON: Getting some new information here back in Boston, so bear with me. Drew Griffin is right here. Drew standing by. Drew just walked up to me with this, right out of the box, and you're saying --

DREW GRIFFIN, CNN CORRESPONDENT: This is the Spanish company maker that made this. It's a company in Spain and you could see it's "Made in Spain" on the bottom. This from the serial numbers that were given out by the FBI bulletin. We believe it's the exact same pot.

You will see if you guys can look in closely it will --

LEMON: Right here to this camera.

GRIFFIN: It should have the 6-L on the bottom. We're just pulling this out. It says gas/electric. We've seen that in one of the --

LEMON: Six-cell right here.

GRIFFIN: In one of the photographs. And I will move my finger over this way, and you will see if you can move it right there fellows, the 6-L. These are identifying marks that we saw in the actual crime scene photos.

LEMON: Let's see if we can run it.

Is that good, can you guys see that? 6-L?

UNIDENTIFIED FEMALE: That's it.

GRIFFIN: Now, we did know yesterday that some pieces of this pressure cooker were found on the roof. And from our Fran Townsend, we know it was the lid -- the lid of one of these that apparently was found on the roof at the crime scene.

These are very common, 50,000 shipped to the U.S. We just looked up within this area code -- with zip code, I should say -- and nine different stores sell these probably within a mile of us.

LEMON: Well, I was saying to the folks on the air and the people here earlier, I was telling Chris Cuomo and John Berman, I had one of these in college. My mother cooks with these. From time to time, defending on which one you get, if you leave it on too long or the pressure gets too hot, it will explode. You'll have food everywhere.

It's originally intended for food but if you put ball bearings in here. If you put nails, if you put BBs in here and the pressure gets high enough --

GRIFFIN: And remember crude device, but you pack it in, pack it in, pack it in -- and then there is some kind of ignition inside here, with this lid which pops on and tightens -- we're not very good. This is not a cooking show. But anyway, it tightens and stops. So now you have all this heat building up inside as that -- let's say it's black powder, we don't know for sure but let's say it's black powder. The heat builds up inside, it has nowhere to go, it has nowhere to go and then all of a sudden, boom.

That's the explosion and then everything inside comes out. The lid flies off presumably to the roof. This may blow out in various directions, and you can imagine just number one, how dangerous that would be. Number two how easy this is to put in a bag, backpack, anything you want.

LEMON: And look, let's talk about this. This is what they're going to use to try to piece together this information. They're going to use this top -- keep that top there visible for you and you can focus on it. They're going to use this to rebuild it. They said they're also going to use other fragments. That backpack -- if we could put up the pictures of the backpack, there are pictures of the markings which they believe to be from this particular pressure cooker.

There are also fragments that include a circuit board, that may indicate that the bombs were detonated on a timer Drew rather than a remote control. This is all important information. No matter how small or as big as our Fran Townsend found out as a pressure cooker top that they found.

GRIFFIN: That's right. All of that is very interesting and extremely valuable. When and if -- when they catch this person, to convict him. What is interesting about this is now we know where this thing may have been sold. The serial number may or may not really tell us exact where it was purchased, because serial numbers are generally used I believe for warranty recalls, et cetera but the police can now go up.

There's nine stores within a mile here. They can start with that. Spread out beyond that. Spread out beyond that and go ask these clerks, "Did anybody buy these that were weird."

LEMON: And you say it's really common. It's not just saying you can grab that bag right there. It's not to say you can get this at any store. You can get it at Wal-Mart; you get it on a Target. You just went over to the Williams Sonoma, and said hey, do you have this kind of -- and there it is.

GRIFFIN: -- barrel I think, seldom. Yes, I think they delivered 50,000 units last year. We're still trying to -- the company is in Spain, we reached out to them. Our London bureau has reached out to them. We have not gotten a comment back. And as far as we know, the federal authorities have not reached the company in Spain. That's according to the Spanish company's London-based PR firm.

LEMON: And some people may be wondering why are you showing this? Are we teaching people. Not really because it's so easy to do this. I mean you look at Timothy McVeigh, when you look at other home-grown terrorist or just around terrorists the world over. They use material that you can find in everyday life.

GRIFFIN: Don, I'm going to tell you why we're telling you this -- ok, look. This is not -- you could go on the Internet and you could to try to build a bomb. It's not that easy. So look. Do you know anybody is in their backyard playing with this, walking back and forth to his garage with something like this. You found a damaged one of these out in a field somewhere -- call. I mean come on.

LEMON: Yes. And that's what police are saying. That's why they're asking to turn in video or pictures, or you may not think the information that you have means anything, but if you saw anything that you thought looked suspicious or made you think twice, to call them.

GRIFFIN: Look at the cleaning person who found one of these inside a house on a kitchen table that had never seen one before. Who knows? That's the kind of tip they need to find the person.

LEMON: Drew griffin, you can see why he is part of our investigative team here at CNN. Thank you again. This is believed to be the exact one that the bomber used, the exact serial number and type. Our Drew Griffin just purchasing one and bringing it here now. And that's the exclusive information that CNN has about this.

This one, similar to this, found on the roof, very near the marathon site. That's according again to our security expert Fran Townsend. Drew Griffin, thank you very much.

More information right after the break.

(COMMERCIAL BREAK) COSTELLO: All right. We want to take you right to Oklahoma City. There are reports -- there's been breaking news. You see that U-Haul truck sitting there, sitting in downtown in Oklahoma City. It is unattended; police believe it was stolen. They do not know what is inside. Of course, the bomb squad is on the scene because the entire country is on edge in light of what happened at the Boston Marathon.

This is very near where the Alfred P. Murrow federal building used to be. As you know, that building was bombed back in 1995 by Timothy McVeigh. So just as a precaution, police are checking out this unattended U-Haul van. All of the city and state offices have been evacuated just as a precaution until police and the bomb squad, figure out what, if anything is inside this U-Haul. Again, it could be something, it could be absolutely nothing. We just don't know. But we do know that Downtown Buildings and Oklahoma city have been evacuated in light of this truck.

We'll have much more information in the hours to come on CNN. Thank you for joining us today. For Don Lemon, I'm Carol Costello.

The next hour of NEWSROOM after a break.

(COMMERCIAL BREAK)

COSTELLO: I'm Carol Costello, thank you for joining us. We'll get to Boston in just a second but we want to show you this U-Haul truck. It's parked right near the city hall buildings in Oklahoma city.

Police do not know what is inside this van. They do know it is unattended. The bomb squad has been called in.